In fact, it has been said before that BYD's fourth-generation DM technology will be divided into two directions, that is, the existing performance-oriented architecture will be classified as a DM-p system, and at the same time, an economy-oriented DM-i system will be launched.
This is actually quite normal. With the development of new energy technology, the performance of batteries and motors continues to improve, giving major manufacturers more ways to play. Now major car companies are pushing PHEV models. As a pioneer of plug-in hybrid technology, it is not surprising that BYD wants to go deeper.
Last night, BYD officially announced that it would launch the DM-i super hybrid technology featuring "ultra-low fuel consumption" and exposed some parameters and infrastructure. However, the key technical information is not yet available. Seeing that everyone's attention is relatively high, Che Jujun tried to explain it to everyone from a technical point of view.
the first and fourth generation of DM technology "turned the rudder"
BYD DM technology has been developed for more than ten years, and the earliest generation was introduced in 28. Since the second generation in 213, the main structure of BYD DM technology has been basically laid, that is, the dual-clutch gearbox is used as the power splitting device, and the engine and motor are split through it.
the biggest feature of BYD's system is that its power is really strong, and it can be divided into EV mode and HEV mode. In EV mode, it is driven by two motors, while in HEV mode, the engine and the two motors can work together. Different from the HEV architecture of Toyota Honda, the HEV mode of BYD's system can directly superpose the power of three power sources, which is so simple and rude. For example, the comprehensive power of Han DM can reach 321kW, the comprehensive torque of the system is 65N·m, and the acceleration time of -1km/h is 4.7 seconds, while the comprehensive power of Camry is only 16kW, so it is impossible to make the engine and motor do their best at the same time.
If we simply compare the absolute power, BYD has no rivals in its class. The 1-kilometer acceleration of the 215 Tang DM has reached 4.5 seconds, and the same class model has not even approached it.
In the automobile world, "fast" is actually a very "valuable" indicator. For example, the price difference between the 28 and 33 versions of Magotan is 33,, while the price difference between the 33 and 38 versions is 3,. The main difference is that the latter is faster and more powerful.
however, the disadvantage of BYD's DM system is that whether it is a dual-engine four-wheel drive or a three-engine four-wheel drive, it depends on the motor, that is, it needs sufficient power. Once the power is insufficient, the power performance of BYD DM models will be greatly reduced, and the fuel consumption is not as good as that of pure fuel vehicles of the same class.
users who buy PHEV models are often not very convenient to charge. If they have independent charging piles at home by default, they often choose Model directly. 3 pure electric vehicles, because the pure electric cruising range is longer, the performance is not bad, the system is simple, the failure rate is low, and the car cost is lower.
so there is a problem. the "fast" of pure fuel vehicles is valuable, and the "fast" of pure electric vehicles is also valuable, but the "fast" of BYD DM system is worthless. Tang DM can run for 5 seconds as early as 5 years ago, but it can't be sold at all.
In fact, this is not only the trouble of BYD, but also the trouble of all car companies pushing PHEV models. On the one hand, they hope to push PHEV models to get new energy points, and of course, they also hope to do a good job in performance. On the other hand, many users buy PHEV models back, that is, when they are using pure fuel vehicles. How exciting the performance advertised by the manufacturer is, and the chances of users using it are not great. The ultra-low fuel consumption promoted by PHEV models is often sneered at by users, because it costs more fuel than pure fuel vehicles in the feed state.
So since this year, car companies that have gradually touched the "doorway" have changed their tune. For example, GAC New Energy began to promote its PHEV model, which saves fuel without charging. SAIC eMG? 6. Propagandize that the fuel consumption can reach 3.9L/1km under the condition of B feed.
BYD chose to launch the DM-i system, which actually caters to this demand to some extent. It is for those users who need new energy licenses but the charging conditions are not good. From a performance-oriented system to an economic-oriented system, BYD has made great determination.
second, the DM-i super hybrid system looks beautiful
but unlike SAIC and GAC, BYD's new system is completely different from the previous architecture, and it can even be said that it has undergone earth-shaking changes.
Let's take a look at the official information released by BYD. The new system consists of a brand-new 1.5L naturally aspirated engine, an E-CVT gearbox and a high-capacity battery. Wait, as I said before, BYD's DM system uses a dual-clutch gearbox, which is a physical gearbox, as a power shunt device. Other mainstream PHEV manufacturers, such as Geely and Volkswagen, are also like this.
however, the DM-i hybrid system has taken another road, which uses E-CVT as the power shunt device. In fact, the E-CVT has nothing to do with the mechanical CVT gearbox. Although Toyota and Honda have different control methods of E-CVT, on the whole, it is used as a power distributor. It does not have a physical gear, but regulates the speed of the engine and motor to determine when to use electricity, when to use oil, when to use oil and electricity together, and what the ratio is.
its advantage is obvious, that is, in theory, as long as it is well controlled, the distribution of oil and electricity can be scientific enough to realize energy saving to the greatest extent. The disadvantage is that the idea is simple, but the control is very complicated. It is so complicated that Toyota has published a lot of patents, but almost no manufacturers have followed up, because it is hard to do it and it is difficult to achieve similar results. Therefore, BYD's sudden "becoming a monk halfway" to build an architecture with E-CVT as the power shunt device has no experience accumulation. To be honest, it is not very promising.
in order to achieve better fuel consumption, BYD developed a 1.5L naturally aspirated Atkinson engine.
at present, the truly mass-produced engines have the highest thermal efficiency, which is Mazda's compression-ignition engine, with a thermal efficiency of 43%, followed by the 2.5L Atkinson engine on Toyota Camry, with a thermal efficiency of 41%. The turbocharged engine is better than Nissan's 2.T variable compression ratio engine and can only achieve 39%.
that is to say, even in the era when the whole people develop turbines, naturally aspirated engines still have certain advantages in terms of pure thermal efficiency. Of course, a bunch of domestic engines with excellent thermal efficiency have emerged this year. For example, Dongfeng claims to have achieved a thermal efficiency of 42%, and GAC claims to have achieved a thermal efficiency of 43%. These two engines are also 1.5T turbocharged engines, so I will not comment until the actual mass production.
Atkinson cycle, that is, the combustion mode with compression ratio less than expansion ratio, has been repeatedly proved by two fields, which can really improve the efficiency of the engine, but the performance, especially the low-speed torque, will be worse. However, there are few working conditions of hybrid engine running at low speed, and the vehicle is mainly driven by motor at low speed, so this is not a problem.
So BYD chooses to make a 1.5L naturally aspirated Atkinson engine, which is really easy to achieve higher efficiency in theory.
let's compare this special plug-in engine announced by BYD. Compared with the same 1.5L Honda hybrid engine, its compression ratio is higher, and its power and torque are slightly superior. Compared with Toyota's 1.8L hybrid engine, its performance is not inferior. And the thermal efficiency has reached an astonishing 43%, which is the same as Mazda compression ignition engine. The official claims that the new model can control the comprehensive fuel consumption within 4L/1km.
According to the information disclosed by BYD before, the economic version of DM system will be installed on Qin DM and Song DM, and even Qin, which is relatively small, has the same size as Lingpai and Lei Ling. In other words, the overall efficiency of BYD's system will be higher than that of Liangtian, which has been doing it for more than ten or twenty years.
3. What are the problems of DM-i system
In Che Jujun's view, the biggest problem of this system is that it is too "perfect". According to BYD's previous statement about DM-i, they do not intend to make a two-field HEV architecture. Because the battery under the HEV framework is too small, it can't support the long-term pure electric operation of the vehicle.
If BYD chooses to be PHEV, it must give full play to the advantages of large-capacity batteries. That is to give full play to the advantages of the motor, and its performance is stronger than that of the two-field HEV model, and now it is announced that the fuel consumption is lower and the efficiency is higher, which simply accounts for both ends.
and BYD also said that the cost of DM-i model is lower, only 2, yuan more than that of fuel version. And the existing Qin Pro? DM is more than 5, yuan more expensive than the fuel version. The basis for PHEV models to enjoy state policy subsidies is that the cruising range of pure electricity should reach at least 5km, and the higher the better, so the cost of the battery, which is close to 1,, cannot be saved. Although the dual-clutch gearbox is cancelled, it is very difficult to control the cost by adding the E-CVT gearbox, plus the motor and control system.
as an analogy, Honda has just mass-produced a 1.5L hybrid system. The price of the hybrid version is 4, yuan higher than that of the fuel version. Toyota has made some concessions on the hybrid assembly of A-class cars, but the difference is still about 2, yuan. Both batteries are very small, and the cost is about two thousand yuan.
and its brand-new engine is completely unbelievable. First of all, it adopts an ultra-high compression ratio of 15.5:1. All car companies know that increasing the compression ratio can improve the engine efficiency. Why don't they do this? Because after the compression ratio is raised, the knock will increase, and the engine will run unsteadily, but it will not achieve the desired effect.
Mazda has made great efforts to develop a set of spark plug ignition control compression ignition technology, which sounds all around the mouth, but the actual control is more complicated, but it only increases the compression ratio to 15:1, at the cost of adding 95# gasoline. BYD has surpassed it in an understatement, and according to the official information, BYD's new engine does not use any new technology. Atkinson cycle+high rolling inlet+cooling EGR are actually common solutions in the market.
and BYD itself has a 1.5L self-priming engine, and now it's on Qin Pro, and its performance is just plain in all aspects. Because BYD's focus is no longer on the self-priming engine, it has not been studying and improving the performance of the self-priming engine like Mazda. It's really incredible that such a "big move" suddenly broke out. It's going to be super early. What are you waiting for for so many years?
high probability, this DM-i is a new concept created by BYD, just like the IGBT technology and high-performance silicon carbide module that BYD hyped wildly before. After a long time, the stock price was speculated, and the result was nothing. Che Jujun counts the insured amount of new cars every month. There is often a big gap between BYD's official sales volume and the insured amount. However, many users feedback that they can't get cars, and the supply is in short supply. I really don't understand where BYD's cars are sold.
the actual situation is unknown. But one thing has to be said, no matter how much the manufacturer publicizes, everyone must take the quality of the final mass-produced products as the judging standard, and the products are good enough for consumers to support them with real money and silver.
summary of car gathering
According to the information disclosed by BYD, its first-generation DM-i system is stronger than Toyota and Honda, and it is all-round. Better performance, lower fuel consumption and lower cost.
If it comes true, you can buy a hybrid version of Qin Pro for 1, yuan. Its performance is better than that of Lei Ling twin engines. It can be driven as a pure electric vehicle, and the fuel consumption can be controlled within 4L/1km in case of power loss, and it can also be licensed as a green brand. This is not just a big killer, it will directly become the "terminator" in the existing A-level auto market.
But according to BYD's historical performance, Che Jujun thinks that the water is very heavy. It's unreasonable to go from to 11 at once. For these data, Che Jujun is skeptical.
But if BYD really makes it, Che Jujun will be very happy to be slapped in the face and make it all come true. It is always a blessing for our consumers to have more models with real strength on the market.
This article comes from the author of Chejia, car home, and does not represent car home's standpoint.